Adding machine spool



June 29, 1965 w. D. LANDGRAF ADDING MACHINE SPOOL Filed July 10, 1963 iiPRIOR ART INVENTOR UJAUYEQ Dinuoenap BY M K /Q/ ATTORNEY S United StatesPatent 3,131,741 ADDHQG MACHINE SPOGL Walter D. 'Landgraf, 4808 W. 96thPlace, Oak Lawn, Ill. Filed July 10, 1963, Ser. No. 294,093 2 Claims.(61. 197-475) The present invention relates generally to spools, and

more particularly to non-collapsible plastic spools for adding machineribbons.

In accordance with the prior art ribbons for typewriters and addingmachines have been wound on metal split rings. The split in the ring isessential to enable a reversing mechanism to sense that the spool hasbeen exhausted of ribbon. Because the spool is split it collapses if thetension on the ribbon winding equipment varies slightly while a ribbonis being wound on a spool. In consequence, the spool will not fit thedriving spindle of the machine in which it is to be installed.

In accordance with the present invention, a ribbon spool is fabricatedof plastic, in one piece, generally a hollow cylinder. Provision forholding a ribbon end to the spool consists of a pair of parallel slotsformed in the wall of the cylinder, extending halfway of its length inan axial direction, and spaced to leave a post for accepting alengthwise slit in the ribbon located adjacent its ends.

A gap is provided for the reversing mechanism, which extends about 80%up, in a radial direction, leaving a bridge to complete the cylinder.-From this bridge a tongue extends inwardly of the cylinder and fits acorresponding slot in driving spindle, acting as a driving or couplingelement for the spool.

Provision of a bridge and tongue (1) prevents collapse of the spool,regardless of tape tension during winding, (2) provides a positive drivefor the spool, (3) prevents the spool being installed upside down orotherwise incorrectly.

It is, accordingly, a broad object of the invention to provide a novelspool for an adding machine ribbon.

It is another object of the invention to provide a spool for an addingmachine ribbon which includes a gap for accepting a reversing mechanismlever, bridged at one end to provide strength and rigidity, and alsopreventing incorrect installation of the spool and having an inwardlydirected tongue associated with the gap to assure positive coupling withthe driving spindle of the machine.

The above and still further objects, features and advantages of thepresent invention will become apparent upon consideration of thefollowing detailed description of one specific embodiment thereof,especially when taken in conjunction with the accompanying drawings,wherein:

FIGURE 1 is a view in perspective of the conventional adding machinespool mount and reversing mechanism;

FIGURE 2 is a view in perspective of a spool according to the invention;

FIGURE 3 is a vie-w in perspective of a spool and spool mount;

FIGURE 4 is a view in top plan of the structure of FIGURE 3;

FIGURE 5 is a view in section taken on line 55 of FIGURE 4;

FIGURE 6 is a view in bottom plan of the structure of FIGURE 3; and

FIGURE 7 is a view of the spool mount of FIGURE 3 in side elevation,taken with spool removed.

Referring now to the drawings, FIGURE 1 illustrates a driving andreversing mechanism for an R. C. Allen adding machine. A bottom flange10 is provided with a central key slotted opening 11, for driving theflange by means of a keyed pin extending therethrough (not shown).Surrounding the opening 11 is an upstanding 3,ll,74l Patented June 29,1965 hollow cylindrical mount 12 for a spool, the mount having an axialslot 13 to permit ingress of a sensing lever 14. The latter extends upthrough a slot 15, sufiiciently long to enable the lever 14 to assumepositions interiorly or exteriorly of the mount 12. The lever 14 isintegral with an element 16, pivotally secured by a rivet 17 to theflange 10, and spring biased by a spring 18 to a position outside ofmount 12. In normal operation the lever 14 is forced inwardly of mount12, and the ribbon spool then slipped over the mount 12. The usual spoolcontains a gap through which the lever 14, biased outwardly by spring18, senses presence or absence of ribbon on the spool. When absence issensed the lever 14 is pulled through slot 13 by spring 14, and operatesa ribbon reverse mechanism.

My novel spool is illustrated in FIGURE 2, wherein is displayed acylindrical plastic structure 20, having a slightly larger innerdiameter than the outer diameter of mount 12, so that it can he slippedthereon. The cylindrical spool 20 includes a gap 21, extending axiallyfrom the bottom edge 22 of cylindrical spool 20, to a point near its topedge 23, at which point the gap 21 terminates and a bridge 25 replacessame. Thereby at least a portion of the circumference of cylinder 20 issolid and rigid, so that cylinder 20 cannot collapse due to excessribbon tension.- A tongue 26 extends inwardly of bridge 25, and is justwide enough to mate with slot 13. The tongue 25 thus provides a positivedrive or coupling for the spool 20. The tongue 26 is so located that thelever 14 can clear same, when installation is correct. If the spool isinstalled upside down the lever cannot operate.

At a position opposite to the tongue 26 are located two slots 30, 31,which are separated by a pin 32 of solid material. The slots extendabout one half the height of the spool 20, from the top edge 23. A slitis cut near the end of the ribbon 35, which extends over the pin 32, thelatter then serving as an anchor for the ribbon 35.

In operation, the slot 34 in ribbon 35 is placed over pin 32 and theribbon 35 wound on spool 20, as in FIGURE 3. The lever 14 is thenpressed inwardly of mount 12 and the wound spool mounted. Spring 18 thenpresses against the ribbon 35, through slot 13, and when the ribbon isentirely unwound can emerge into the position illustrated in FIGURE 3,to effect ribbon feed reversal.

While I have described and illustrated one specific embodiment of myinvention, it will be clear that variations of the details ofconstruction which are specifically illustrated may be resorted towithout departing from the 1 true spirit and scope of the invention asdefined in the appended claims.

What I claim is:

1. A ribbon spool for installation on a rotary cylindrical drive spindlehaving a flange surface extending from the base and normal to the axisthereof, and having associated therewith a reversing lever pivotallyattached to the underside of said flange surface, said lever includingan upstanding pin extending through a cutout in said flange surface,said pivotal attachment and said cutout permitting movements of said pinsubstantially radially of said axis between a biased position exteriorlyof said spindle and a ribbon sensing position interiorly of said spindlethrough an associated gap therein, said spool comprising a hollowcylinder arranged to mate with said spindle and to seat against saidflange sunface, a slot extending through the wall of said cylinder fromthe seat end thereof to a point adjacent the other end thereof, a tongueportion projecting inwardly of said cylinder along the terminus of saidslot and substantially coextensive with the width of said gap, saidtongue portion arranged to mate with said gap to align said slottherewith and to couple said spool to said spindle for rotationtherewith, said slot having a length sufficient to permit said pin totravel freely therethrough in the absence of ribbon on said spool, saidtongue portion projecting inwardly of said spindle beyond the point ofmaximum inward travel of said pin when said spool is seated on saidspindle, so that said pin and tongue portion interfere to preventseating of said spool against said flange surface s in the event ofimproper installation of said spool.

2. The combination according to claim 1, wherein a References Cited bythe Examiner UNITED STATES PATENTS 7/62 Bishop 197-175 6/ 63 Landgraf197175 MERVIN STEIN, Primary Examiner.

1. A RIBBON SPOOL FOR INSTALLATION ON A ROTARY CYLINDRICAL DRIVE SPINDLEHAVING A FLANGE SURFACE EXTENDING FROM THE BASE AND NORMAL TO THE AXISTHEREOF, AND HAVING ASSOCIATED THEREWITH A REVERSING LEVER PIVOTALLYATTACHED TO THE UNDERSIDE OF SAID FLANGE SURFACE, SAID LEVER INCLUDINGAN UPSTANDING PIN EXTENDING THROUGH A CUTOUT IN SAID FLANGE SURFACE,SAID PIVOTAL ATTACHMENT AND SAID CUTOUT PREMITTING MOVEMENTS OF SAID PINSUBSTANTIALLY RADIALLY OF SAID AXIS BETWEEN A BIASED POSITION EXTERIORLYOF SAID SPINDLE AND A RIBBON SENSING POSITION INTERIORLY OF SAID SPINDLETHROUGH AN ASSOCIATED GAP THEREIN, SAID SPOOL COMPRISING A HOLLOWCYLINDER ARRANGED TO MATE WITH SAID SPINDLE AND TO SEAT AGAINST SAIDFLANGE SURFACE, A SLOT EXTENDING THROUGH THE WALL OF SAID CYLINDER FROMTHE SEAT END THEREOF TO A POINT ADJACENT THE OTHER END THEROF, A TONGUEPORTION PROJECTING INWARDLY OF SAID CYLINDER ALONG THE TERMINUS OF SAIDSLOT AND SUBSTANTIALLY COEXTENSIVE WITH THE WIDTH OF SAID GAP, SAIDTONGUE PORTION ARRANGED TO MATE WITH SAID GAP TO ALIGN SAID SLOTTHEREWITH AND TO COUPLE SAID SPOOL TO SAID SPINDLE FOR ROTATIONTHEREWITH, SAID SLOT HAVING A LENGTH SUFFICIENT TO PERMIT SAID PIN TOTRAVEL FREELY THERETHROUGH IN THE ABSENCE OF RIBBON ON SAID SPOOL, SAIDTONGUE PORTION PROJECTING INWARDLY OF SAID SPINDLE BEYOND THE POINT OFMAXIMUN INWARD TRAVEL OF SAID PIN WHEN SAID SPOOL IS SEATED ON SAIDSPINDLE, SO THAT SAID PIN AND TONGUE PORTION INTERFERE TO PREVENT SATINGOF SAID SPOOL AGAINST SAID FLANGE SURFACE IN THE EVENT OF IMPROPERINSTALLATION OF SAID SPOOL.